He was relatably miserable because his sister was super annoying and shitty human being, and her friend that was into him was hardcore creep. Seriously, how do you people can call him "cunt" when the series MC is weirdly lovable but objectively awful human being (now significantly less awful, but even in this chapter the "joke" was that she constantly sexually harasses her friends, objectively asshole behavior). That's some prime example of "protagonist centered morality" where Tomoko could be annoying cunt to her brother, but he's the one called "cunt" for being annoyed by it.
Him being boring is valid critique, or being annoyed by the harem stuff, but calling him asshole because he doesn't like the asshole protagonist or her creepy/annoying friends is wild hypocritical bullshit. I don't remember him ever disliking Asuka or A-chan, or Emoj Mk 2, who are few of the actually nice and socially-adjusted girls in Tomoko's class. Most of the rest of them, while funny in manga, would be annoying as hell if met in real life.